Golden Retrievers are one of the most popular dog breeds in the country. They are friendly, easy with kids, and obedient. A heartbreaking new study, though, shows more than half of all Goldens die of cancer.

Researchers claim 61 percent of Goldens die of cancer. Now, there's a nationwide survey that's tracking 3,000 Golden Retrievers through their lifetime. It's the first study of its kind.

Holly Israel of Raleigh enrolled her dog, Sandy, in the study. Sandy is dog No. 1796. She enrolled Sandy after her other Golden Retriever, Rosy, died from the disease.

"[Rosy] was growing a tumor in her abdomen, in her intestine. No one realized that until the day she couldn't get up anymore. So she went to the vet, got diagnosed, and passed away the same day. She was suffering so much," Israel recalls.

Now, every year, Holly takes Sandy to the vet to get DNA samples from her blood, urine, fur, and toenails. She also fills out a 200 question survey about Sandy's habits, and environment.

"What they eat, where they sleep, things they're exposed to, yard chemicals, what types of floors they sleep on, what type of pipes your water is coming through, how much exercise they get, their interaction with other dogs. They want to know their personality."

Holly fills out every question gladly.

"We're doing this for science, but it also means something for me. It's in Rosy's memory that Sandy went and got involved in the study and then hopefully down the line any future Golden Retrievers that I have may benefit from the results."

Scientists will track the test dog's DNA for every year of their life and look for trends. The information will help scientists identify ways to better prevent cancer and other diseases in Golden Retrievers. And researchers believe what they learn from these dogs will improve the health of all dog breeds. It will even help research cancer in humans.